Launched by the state's health department earlier this week, the testing collected samples of 3,000 supermarket shoppers from 40 locations in 19 counties in the state, according to Cuomo.

The preliminary results suggest the real number of total infected in the state's 19.45 million people could be ten times higher than the official data, which stood at 263,754 as of 2 p.m. local time (1800 GMT) on Thursday, according to a tally kept by Johns Hopkins University.

People who have tested positive in the antibody testing are those who were infected with coronavirus and then recovered. The testing offers a snapshot of the infection rate statewide and is considered a major step in determining when and how to restart the economy.

New York City has shown a 21.2 percent positivity rate in the testing, higher than anywhere else in the state. Long Island had a 16.7 percent positivity rate, while 11.7 percent in Westchester county and Rockland county tested positive. The rest of the state registered 3.6 percent.

The racial breakdown shows the positivity rates of Asians, Blacks, Latinos and Whites in the state are 11.7, 22.1, 22.5 and 9.1 percent, respectively.

Meanwhile, 12 percent of females tested positive and 15.9 percent of males tested positive.

The results also indicated that the real mortality rate could be around 0.5 percent in the state, much lower than the 7 percent calculated from official numbers.

However, it's not sure how telling the results are. "These are people who were out and about shopping. They were not people who were in their homes, they were not people who were isolated, they were not people who were quarantined," said Cuomo.

Dr. Oxiris Barbot, New York City's Commissioner of Health, said on Thursday that the 138,000- plus confirmed COVID-19 cases in the city is just "the tip of the iceberg" as diagnostic testing was very limited at the beginning of the outbreak.

"It wouldn't surprise me if at this point in time we have probably close to a million New Yorkers who have been exposed to COVID-19," she said at the mayor's daily briefing.

New York state has registered over 19,500 COVID-19 fatalities by Thursday afternoon, with over 15,000 in New York City, according the Johns Hopkins' tally.